In the books

In the A Song of Ice and Fire novels, Rhaella is the wife and sister of Aerys II and the mother of Rhaegar, Viserys and Daenerys. Aerys had married her partly out of duty, since he had lusted after Joanna Lannister. The siblings apparently loathed each other and their marriage was loveless, becoming violent and abusive towards the end.

According to Jaime, Aerys and Rhaella used to avoid each other most of the time - except when Aerys had someone burnt to death. The Mad King would have been aroused by that action, then he would pay visit to Rhaella and molest her in extremely brutal manner. At one of those occasions, Jaime and Jon Darry stood at guard outside the queen's bedchamber, and heard her cry helplessly "You're hurting me". Jaime felt bad about that and told Darry "We are sworn to protect her as well". Darry answered "We are, but not from him." According to the queen's maids, on the next morning she looked as if some beast had savaged her, clawing at her thighs and chewing on her breasts. That vicious molesting might have increased the loathing Jaime has already felt toward Aerys ever since the execution of Rickard Stark and his son.